Absorbent sheet products have become very popular for personal care applications for both adults and babies. Examples include face or body cleansing wipes, wipes for skin treatment, and skin conditioning wipes. These wipes or pads are nowadays commonly used to apply skin care compositions or make-up to the skin as well as for the removal of, for example, feces, urine or make-up.
In order to achieve such products which are well accepted by the consumer high standards, for example, in terms of softness, absorption and mechanical strength have to be met. Especially when used for make-up removal in rather sensitive areas like the area around the eyes the customer is very critical in the choice of products. It is, for example, immediately noticed if a pad or wipe lacks softness. Also, it is considered to be disadvantageous if an absorbent substrate tends to fray or fuzz as is for example the case with dabbers. Nevertheless, pieces of non-woven or cotton wool are still frequently used as a basis for make-up removal lotions.
In skin caring or cleansing operations active ingredients are usually not directly applied to the skin but with the use of pads or wipes to insure a more regular distribution. Also, the fingers are kept free of any oily lotions. Skin cleansing operations usually require pads and wipes which regularly take up soilage or make-up. In all cases the pad material should not irritate the skin even when repeatedly used. In addition, the absorbent capacity should meet high standards. In the recent years major efforts have been spent to improve the softness and absorbency characteristics of wipe and pad materials.
Initially, wet wipe products were made of traditional non-woven materials based on paper making technology (pulp based products). These products although accepted suffer in the softness of the fabric material. The introduction of the spunlacing non-woven technology offers products that compared to traditional paper based products are superior in terms of softness and strength. This is mainly due to the use of long soft fibers such as the rayon and PET-PP or mixtures of these fibers in the spunlacing process and also to the fact that during the spunlacing process no binder is added to the fabric.
However, even with these products, especially having higher basis weights, e.g. of about 80 g/m2 or more, it is difficult to maintain the original structure of the wipe when impregnated with, for example, soilage or lotions. Ordinary pads usually collapse upon impregnation with these compounds thereby losing their absorbency, strength and softness characteristics.
Hence there is still a need for absorbent pads or wipes for cosmetic and/or dermatological applications. As becomes apparent in the following there have been several attempts to remedy the deficiencies of existing cosmetic or dermatological wipes and pads.
According to JP 2003095868 A a make-up wipe when comprising a non-woven fabric which contains ultra-fine fibers having a single fiber fineness of less than 0.5 dtex should be capable of efficiently removing a cosmetic without irritating the skin. The ultra-fine fibers have to occupy around 20% of the surface area of the non-woven fabric.
According to U.S. Pat. No. 5,626,571 the softness of non-woven webs or fabrics can be improved by a mechanical post-treatment, for example, by incrementally stretching a non-woven web. This can be achieved by employing opposed pressure applicators having three-dimensional surfaces which at least to a certain degree are complementary to one another, or by permanently stretching an inelastic base non-woven in the cross-machine direction. However, these non-woven fabrics still exhibit a relatively low abrasion resistance and tend to fuzz during application. This disadvantage can according to WO 02/31245 be overcome with a non-woven web having a consolidation area of at least 30% which is obtained by thermal bonding. With this modification the softness of the web should not be affected.
In addition, bond patterns have been utilized to improve strength abrasion resistance in non-woven fabrics while maintaining the softness as for example disclosed in U.S. Pat. No. 5,964,742.
Wipes having an improved softness which are less harsh on the skin compared to woven cloth or paper based pads and which are stronger than cotton based non-woven wipes shall according to EP 750 062 A1 be provided by non-woven webs having a basis weight of from 20 to 130 g/m2. These wipes have to exhibit a specific coefficient of friction and have to be produced by hydroentangling or needlepunching.
In WO 03/022116 a cosmetic sheet product for skin applications is disclosed which has high absorbent capacity for active agents, good releasability of absorbed active agents and a good combination of softness and strengths. This soft non-woven fibrous cosmetic wipe material has to contain a non-woven fibrous layer having a z-direction loft from the backing of at least 0.5 mm where the non-woven fibrous layer material is bonded to a backing layer. This z-direction loft is formed by arcuate portions between areas of bonding of the non-woven layer to the backing which arcuate portions comprise from 20 to 99% of the wipes cross-sectional wiping area. Such a wipe can be formed from a broad range of non-woven fabrics and fibers and is not any longer limited to the use of conjugate fibers having at least two crimps per inch or to non-wovens that are bonded at all fiber cross-over points as required by U.S. Pat. No. 5,605,749. According to this latter document to obtain a pad for personal or industrial use which exhibits good compression resilience, high physical strength and abrasion resistance rather complex and specific requirements have to be met.
According to U.S. Pat. No. 4,775,582 also meltblown non-woven wipes are suitable for personal care uses.
EP 750 062 A1 requires the basis weight of non-woven webs to be from 20 to 130 g/m2 and to be produced by hydroentangling or needlepunching in order to be useful as skin cleansing wipes.
From U.S. Pat. No. 5,928,973 a non-woven needlepunch fabric can be derived consisting of 60 to 90 wt.-% lyocell fiber having a length of 2.54 to 15.32 cm, 10 to 40 wt.-% polyester fiber having a length of 2.54 to 15.32 cm and 0 to 30 wt.-% of other textile fibers, wherein the lyocell fibers have a denier in the range of 0.75 to 6 prior to fibrillation and wherein the fabric has been formed by subjecting the fibers to carding, cross-lapping and needlepunching. Particularly preferred fibers comprise crimped lyocell and polyester fibers. However, the fabrics according to U.S. Pat. No. 5,928,973 are still rather harsh and tight and are lacking a sufficient degree of softness paired with a required degree of bulkiness. Fabrics as disclosed in U.S. Pat. No. 5,928,973 are therefore mainly used in automotive or battery applications, as for example described in WO 96/13071.
Also for floor cleaning wipes non-woven substrates are frequently used. In WO 03/050230 such a floor cleaning wipe is described the water-insoluble substrate of which has been impregnated with a liquid composition which is not an emulsion. The water-insoluble substrate consists of two layers wherein the first layer is a polyester non-woven fabric and the second layer is made from a needlepunched cellulose non-woven fabric.
U.S. Pat. No. 6,569,828 B1 discloses a cleaning wipe for dish washing applications wherein the water insoluble substrate consists of a top layer of coarse fibers, for example, made from polypropylene fibers, an absorbent center layer made from cellulose fibers and a bottom layer of fine fibers, for example, made of polyester fibers. Only the center absorbent layer is impregnated with a cleansing composition which also comprises a water-soluble cellulosic polymer besides a surfactant, a solubilizing agent and a preservative.
The cosmetic wipe described in WO 02/072052 is impregnated with an oil-in-water emulsion which can also be a PIT emulsion containing a C12-30 carboxylic acid mono- or diglyceride. The sheet material is preferably made from non-wovens such as wood pulp, polyolefin, polyester or polyamide fibers. Preferably, a mixture of cellulose pulp and a binding material is employed. This non-woven sheet material can be made by a variety of processes such as airlaying, wetlaying or carding. The wipes according to WO 02/072052 should be soft and also provide a softer feel after the application of the wipe without the need to have to add specific fabric softeners to either the finished product or the fibers used as raw materials.
DE 199 17 275 B4 is about a non-woven cleansing wipe made from microstaple fibers and absorbent secondary staple fibers wherein the microstaple fibers are multi-component split fibers from at least two different polymers and wherein the secondary staple fibers are made from viscose lyocell fibers according to the chemical fiber spinning process. In case such a cleansing wipe consists of more than one non-woven layer these layers can be joined by entanglement, lamination or needlepunching. These cleansing wipes exhibit a high abrasion resistance as well as a high absorbent capacity for soilage and also a high strength.
The problem related to conventional non-woven wipe materials still is that they are not well suited to maintain their structure and do collapse when impregnated with lotions or wetted. In addition, it would be desirable to have access to a non-woven which does not loose its soft touch sensation when rubbed on the skin without the need to use large amounts of material.
The object of the present invention has been to provide an absorbent product, e.g. a pad, suitable for cosmetic applications even with rather sensitive areas such as the skin around the eye which is soft and bulky, does not irritate the skin, takes up make-up efficiently and is suited to apply cosmetic and dermatologic lotions to the skin without the risk that the fiber will ravel out, and which maintains its original structure when impregnated with said lotions or when being wetted or having taken up removed make-up.
A further object of the present invention has been to provide an absorbent product which is superior in retaining fluids, such as cosmetic and dermatological lotions, and which in particular holds a liquid such as the aforementioned lotion after having been disposed onto or impregnated into the absorbent product whereby this liquid is prevented from a downward movement due to gravity.